Ten unmedicated patients with Parkinson's disease received sub-threshold 5-Hz repetitive transcranial magnetic stimulation (rTMS) over the primary motor hand area (M1(HAND)) contralaterally to the more affected upper limb. Compared to a midfrontal sham-rTMS, real-rTMS over M1(HAND) was associated with a significant decrease in the global motor UPDRS score 1 h after the cessation of rTMS. This was mainly due to a clinical improvement in the arm contralaterally to the stimulated M1(HAND). These preliminary data suggest that focal rTMS of M1(HAND) may have a therapeutic potential in PD.